Topic: Jimmy just aint right

[79coyotefrg]

   well  last november  Insane  came down and helped me  swap motors,  bubba was by a week or so later  and  finally got it running,  been doing  fine ever since

week ago  sis came in late  after work and told me  it  was missing  and the engine light was flashing
btw  1996 GMC Jimmy  4x4  4 door 4.3 v6

well i  go to autozone  and they pull the codes,  O2  sensor  and  misfire on #2

after pulling the O2 sensor  i called Insane  and spoke with Bubba and Gittinit  and  decided to  rod out the CAT

got that done  it drove fine  still had a bad hesitation but otherwise  MUCH better

well today sis called  and it was  on the road  just up from walmart,  so i  took Mom with me to town  to drive the thing  and  she started it  while i had the hood up, 
started fine  ran good,  but when put in gear the engine  shook violently then died,   did this about 6 times  befor  we  got it to move,   again  only code was a misfire  ,  no  cylinder  determined  just  misfire

now  to me  it  sounds  and acts  like its out of time,  like its  too far advanced,  it tries to kick back when trying to start it , but the computer  controls  all of this  and theres  no way to adjust it

i'm going to pull and inspect the distributo cap,  yes  it has  one coil and a cap,

but besides  it having a crack  im leaning heavily towards  a bad  computer

what  could make it  advance the timing  when it doesnt need it advanced

btw  when running down the road 50mph or more  it runs perfect

[79coyotefrg [OP]]

 Today at 03:44:02 PM 79coyotefrg – cleaned  the mass air  meter thingy  and everything
 Today at 03:43:39 PM 79coyotefrg – replaced the o2
 Today at 03:43:38 PM miner mike – that would make it run ruff 
 Today at 03:43:29 PM 79coyotefrg – yep,  its  just like the timing has been advanced too far
 Today at 03:43:27 PM miner mike – try the 02 sensor
 Today at 03:43:06 PM miner mike – and you only get one code??
 Today at 03:42:43 PM 79coyotefrg – plugs looked great
 Today at 03:42:40 PM miner mike – plugs
 Today at 03:42:31 PM 79coyotefrg – yep single coil
 Today at 03:42:28 PM miner mike – are the plug dry??
 Today at 03:42:20 PM 79coyotefrg – yea     so i gotta  take sis to work 
 Today at 03:42:08 PM miner mike – that is coil not coil packs right??
 Today at 03:41:24 PM miner mike – dang
 Today at 03:41:11 PM miner mike – try the neg cable  glen
 Today at 03:41:11 PM 79coyotefrg – did that,  then it  comes back to misfire  codes,  left cables off for 3 hours,  ran ok, then started  blinking the engine light again
 Today at 03:40:56 PM miner mike – i need a free popup blocker 
 Today at 03:40:34 PM miner mike – they work awsome
 Today at 03:40:28 PM miner mike – i always used snapon scnner glen 
 Today at 03:39:56 PM miner mike – then put back on and see if you get new codes
 Today at 03:39:41 PM miner mike – try taking neg cable off  for like ten minutes
 Today at 03:39:34 PM 79coyotefrg – the hand held  they use at autozone  aint  good 
 Today at 03:39:16 PM miner mike – hard to say with out seeing it
 Today at 03:39:06 PM miner mike – could be puter glen
 Today at 03:39:01 PM 79coyotefrg –   but why dont it say that  in the codes
 Today at 03:38:48 PM miner mike – you need  to have  someone with better scanner  test it
 Today at 03:38:28 PM 79coyotefrg – coputer  controls  that too right
 Today at 03:38:09 PM miner mike – if lockup torque converter goes out it will do tha  and most of the time its just a switch
 Today at 03:37:51 PM 79coyotefrg – that wouldnt make it  spit  and kick back when its  trying to start though 
 Today at 03:36:49 PM miner mike – coud be lock up torque converter glen
 Today at 03:35:51 PM 79coyotefrg –

[Blingn]

Glen do you have any p codes ? besides what you described I am on my works program checking DTC's right now

[79coyotefrg [OP]]

p0300

[Gittinit]

I don't have a clue. It seems like you have the bases covered. It also seems to me like something electrical. It could be something as simple as the coil or as complex as a combination of problems, but considering it was fine then suddenly started this, I would weigh the odds towards it being something simple.

[79coyotefrg [OP]]

it had a p0140 , replaced the o2 sensor  and checked the other 3

then  it started throwing this  misfire code


but  its  acting just like a yota would if  the timing was  way too far advanced

[79coyotefrg [OP]]

one thing i havent done,  im gonna get the old coil  and ignition module  from the old engine and swap them out,  wish me luck


well  and hopefully i dont have a heat stroke    

[Blingn]

ok man great ill have your info in a sec man

[Blingn]

DTC P0300 Engine Misfire Detected (1 Of 2)
 
 
 
 

DTC P0300 Engine Misfire Detected (2 Of 2)
 
 
 
 

Engine Schematic
 
 
 
 


Circuit Description
The crankshaft position sensor and camshaft position sensor detects a misfire, The Vehicle Control Module (VCM) monitors the speed of the crankshaft. The VCM detects a deceleration of the crankshaft that is not associated with normal engine speed reduction. In order to determine if a misfire occurred, the VCM compares the deceleration information to the engine speed and engine load. If a misfire event is determined, the VCM compares the crankshaft position to the cam sensor signal in order to determine which cylinder misfired. The VCM stores the information in separate accumulators for each cylinder. Upon completion (or failure) of the test, the VCM evaluates the number of misfires in each accumulator. If the accumulators are somewhat even or it 3 or more cylinders are misfiring, then this determines that a random misfire has occurred. The VCM also utilizes the input from the ABS wheel speed sensor in order to determine if a rough road condition exists which could cause a crankshaft acceleration and deceleration. If a rough road condition exists, the diagnostic will not run. This DTC is a type B DTC.

Conditions For Setting The DTC



No Throttle Position (TP) sensor DTCs.
No Mass Air Flow (MAF) sensor DTCs.
No Ignition Control (IC) sensor DTCs.
No Vehicle Speed (VS) sensor DTCs.
No Crankshaft Position sensor DTCs.
Rough road is not detected.
The Engine Coolant Temperature (ECT) is between -6.75°C and 95.2°C.
The engine speed between 300 RPM and 5600 RPM.
The system voltage between 9 volts and 16 volts.
The positive throttle position change is less than 4.9% for 100 msec.
The negative throttle position change is less than 2.9% for 100 msec.
A misfire is detected.
Action Taken When The DTC Sets
If the VCM determines that the misfire is significant enough to have a negative impact on emissions, the VCM turns on the Malfunction Indicator Lamp (MIL) after the misfire has been detected on 2 non-consecutive trips under the same operating conditions. If the misfire is severe enough that catalytic converter damage could result, the MIL flashes while the misfire is present.

Conditions For Clearing The MIL/DTC
The VCM turns the MIL off after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

Diagnostic Aids
If the Misfire Index indicates that one bank of the engine is experiencing misfire, the HO2S for that bank may be faulty (i.e. Bank 1 Sensor 1 or Bank 2 Sensor 1). If the Misfire Index indicates that paired cylinders (i.e. cylinders 1-4, 6-3 are experiencing misfire, inspect the Crankshaft Position (CKP) sensor reluctor ring for damage.

The Misfire Index counts the number of misfires. The scan tool can monitor the Misfire Index. There is a current and history misfire counter for each cylinder. Use the current misfire counter in order to determine which cylinder is misfiring. Many different condition could cause an intermittent misfire.

Check for the following conditions:



Check the spark plug wires and the coil wire for the following conditions:
Ensure that the spark plug wires are securely attached to the spark plugs and the distributor cap.
Check the wire routing in order to ensure that cross-firing is not occurring.
If the misfire occurs when the weather is damp, the problem could be due to worn plug wires.
NOTE : In order to test for this condition, spray the wires with water and with the engine running, watch for spark to jump from the wires. If a spark is visible, replace the wires.



Check for contaminated and a low fuel level and the following conditions:
Check the fuel condition and quality. Dirty or contaminated fuel could cause a misfire condition.
If the fuel level is low, contaminants in the bottom of the fuel tank could enter into the fuel metering system.
Test Description
The numbers below refer to the step numbers on the diagnostic table.



If DTCs P0337 (Crankshaft Position Sensor Circuit Low Input) or P0338 (Crankshaft Position Sensor Circuit High Input) are set, this could result in a misfire condition.
In order to duplicate the conditions under which the misfire occurred, it may be necessary to drive the vehicle and monitor the scan tool DTC Set This Ignition Cycle variable.
When checking the spark at the spark plug wires, the spark should be consistent. A few sparks then nothing is no spark.
At this point, the ignition system is OK and the problem may be in the fuel system. Fuel System Diagnosis must be performed in order to determine the cause of the problem.
 
 

[Blingn]

DTC P0140 HO2S CKT Insufficient Activity Sensor 2 (1 Of 2)
 
 
 
 

DTC P0140 HO2S CKT Insufficient Activity Sensor 2 (2 Of 2)
 
 
 
 

HO2S Circuit
 
 
 
 


Circuit Description
The Vehicle Control Module (VCM) supplies a voltage of about 0.45 volt (450 mV) between the HO2S High and HO2S Low circuits. (If measured with a megaohm digital voltmeter, this may read as low as 0.32 volt.) The Heated Oxygen Sensor (HO2S Bank 1, Sensor 2) varies the voltage within the range of about 1.0 volt (1000 mV) it the exhaust is rich, down to about 0.10 volt (100 mV) if the exhaust is lean.

The sensor is like an open circuit and produces no voltage when it is below 360°C (600°F).

The HO2S heater provides for a faster sensor warm-up which allows the sensor to become active in a shorter period of time and remain active during a long extended idle. The DTC P0140 determines if the HO2S to the HO2S circuit has developed an open. This DTC is a type B DTC.

Conditions For Setting The DTC
The Following Conditions will set the DTC:



No Throttle Position (TP) sensor DTCs.
No Evaporation Emission (EVAP) DTCs.
No Intake Air Temperature (IAT) sensor DTCs.
No Manifold Absolute Pressure (MAP) sensor DTCs.
No Engine Coolant Temperature (ECT) sensor DTCs.
No Mass Air Flow (MAF) sensor DTCs.
No intrusive test in progress.
The system voltage measures at least 9.0 volts, The engine run time is greater than 2 minutes.
HO2S Sensor Open Test Enable



A Closed Loop.
The DTC P0141 (HO2S heater) not set.
HO2S voltage greater than 0.299 volts but less than 0.598 volts.
Engine run time is greater than 2 minutes.
HO2S (Bank 1, Sensor 2) voltage is greater than 299 mV but less than 598 mV.
Action Taken When The DTC Sets
With a current DTC set, the Malfunction Indicator Lamp (MIL) turns on after 2 test failures.

Conditions For Clearing The MIL/DTC
The VCM turns the MIL off after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

Diagnostic Aids
A poor connection, rubbed through wire insulation, or a wire broken inside the insulation may cause an intermittent.

Check for the following conditions:



A poor connection or a damaged harness: Inspect the harness connectors for the following conditions:
Backed out terminals.
Improperly formed or damaged terminals.
Poor terminal to wire connection.
Damaged harness.
A faulty HO2S (Bank 1, Sensor 2) heater or heater circuit: With the ignition switch turned ON but the engine stays off, the HO2S (Bank 1, Sensor 2) voltage displayed on a scan tool should gradually drop to below 0.300 volt, indicating that the heater works properly. If not, disconnect the HO2S (Bank 1, Sensor 2) and connect a test light between the terminals C and D. If the test light does not light, repair the open in the HO2S (Bank 1, Sensor 1) ground circuit or the HO2S (Bank 1, Sensor 2) ignition feed circuit. If the test light lights, replace the HO2S (Bank 1, Sensor 2).
The Intermittent test: With a scan tool monitor the HO2S (Bank 1, Sensor 2) signal voltage while moving the related connectors and the wiring harness with a warm engine running at part throttle in a Closed Loop. It the failure is induced, the HO2S (Bank 1, Sensor 2) signal voltage reading changes from its normal fluctuating voltage (above 600 mV and below 300 mV) to a fixed value around 450 mV. This may help to isolate the location of the malfunction.
NOTE : Never solder the HO2S wires. For proper wire and connection repairs, refer to Diagrams.

Test Description
The numbers listed below refer to the step numbers on the diagnostic table.



If the conditions for the setting DTC P0140 exist, the system will not go into a Closed Loop.
This step determines if the sensor or the wiring is the cause of the DTC P0140.
This test checks the continuity of the HO2S 2 High signal circuit.
 
 

[Blingn]

I hope this helps man I also have some test procedures I might be able to get for ya if this isnt enough

[79coyotefrg [OP]]

i will check the crank sensor

thanks Matt

[Blingn]

any time man let me know if you need more info I love to help

[85xcab]

Did you swap the coil for a known good one? I recently ran into a similar problem. The coil had a small rubbed spot letting it jump fire to ground/the intake. It ran like the cam had jumped time, I saw the problem while looking at the engine run in the dark.

[79coyotefrg [OP]]

Did you swap the coil for a known good one? I recently ran into a similar problem. The coil had a small rubbed spot letting it jump fire to ground/the intake. It ran like the cam had jumped time, I saw the problem while looking at the engine run in the dark.

i havent but i will,  i have one  of those 

[blyota91]

I have seen many of those 4.3's with a bad coil wire.  It rubs through on a metal bracket between the coil and distributor.

[79coyotefrg [OP]]

i swapped out the coil,  and  ignition module thingy  next to it

swapped  the crank sensor out,  and nothing is  different,  im convinced  its  the  computer 

[BUBBA]

do you still have the rig you got the motor out of?

[79coyotefrg [OP]]

do you still have the rig you got the motor out of?

no, but im hoping the dealer still does 

[85xcab]

Check the cam timing. ecm failure is not very common.

[79coyotefrg [OP]]

Check the cam timing. ecm failure is not very common.

but its not  adjustable

[Wermz84]

  if I knew anything about american vehicles I'd try to help ya Glen 

[85xcab]

No it not adjustable, but if the chain is stretched and jumped a tooth or two the dist/crank sensor/cam will no longer be in time with each other. Line the timing mark on the balancer up with the timing mark, the rotor should be pointing almost directly at the #1 terminal of the dist cap. If it points directly away from the #1 terminal turn the engine another 360. If it doesn't line up the cam chain has jumped time. It's not common but does happen.
How many miles does the engine have on it?

[79coyotefrg [OP]]

motor  was put in in November of last year

but  since ive been so sick  i  just cant  get over in there, everytime i try to stretch over the grill to  reach  back to the distributor or something i start having bad cramps and have to go

so  tomorrow  my  dealer  is gonna come pick it up  and take it to a shop, and he said  once they check it  we'll decide what to do

ie  either fix it  or  put us in something else

[85xcab]

Good luck I hope it is something easy and cheap that just got missed.
Those engine compartments aren't much fun even when you feel good.

[79coyotefrg [OP]]

well  it has to be blamed on me being so sick lately  because  i cant believe i missed that        

dealer picked it up  and carried it to the shop they use in town

dude  has a  large  computer  to  hook  it up to, not just a hand held.  anyway  it just said  misfire, well DUH

so  dude  pulled the distributor cap  and said  first thing he noticed  was  one of the screws  that hold the rotor down  was missing,  he pulled the other one and removed the rotor  and the other screw  was down beside the trigger thingy     


it runs fine now     i feel like a 


i was   SICK I TELL YA 

[unclejpl4x4]

   

[Lady Di]

 

[79coyotefrg [OP]]

   I CANT HELP IT   



I WAS SICK I TELL YA 

[unclejpl4x4]

it's ok   been there done that